- #1

Ceesa

- 4

- 0

## Homework Statement

A Verdant Power water turbine (a “windmill” in water) turns in the East River near New York City. Its propeller is 2.5 m in radius and spins at 32 rpm when in water that is moving at 2.0 m/s. The rotational inertia of the propeller is approximately 3.0 kg∙m^2. Determine the kinetic energy of the turbine and the electric energy in joules that it could provide in one day if it is 100% efficient at converting its kinetic energy into electric energy.

## Homework Equations

tau=Fr

tau=I(alpha)

KE=0.5I(omega)^2

P=tau(omega)

W=tau(theta)

## The Attempt at a Solution

I can find the rotational kinetic energy using the third equation in the list, and I get 17 J. But I'm having trouble finding the power produced by the wheel, and I wanted to do that because then I can do power x time to find the energy produced in a day. I can't find the torque on the wheel because the wheel is moving at constant velocity and I have no information about friction. I feel like I should use the rotational KE in some way, but dividing the rotational KE by one day to get power won't make sense because they I'd just have to multiply it by one day and be back where I started.

Any help appreciated. :)